Merge pull request #15576 from mkdgs/patch-2

Fix: undefined measuring_units_squared() on update

htdocs/product/class/product.class.php

@@ -35,6 +35,7 @@
  *    \ingroup    produit
  *    \brief      File of class to manage predefined products or services
  */
+require_once DOL_DOCUMENT_ROOT.'/core/lib/product.lib.php';
 require_once DOL_DOCUMENT_ROOT.'/core/class/commonobject.class.php';
 require_once DOL_DOCUMENT_ROOT.'/product/class/productbatch.class.php';
 require_once DOL_DOCUMENT_ROOT.'/product/stock/class/entrepot.class.php';